1. Field of the Invention
The present invention relates to light-emitting module.
2. Related Prior Art
A light-emitting module generally comprises a semiconductor light-emitting device and a package for enclosing the light-emitting device. Such module is used in, for example, the wavelength division multiplexing (WDM) communication system. In the WDM communication system, since a plurality of optical signal each having a particular wavelength is transmitted through an optical fiber, respective optical signal source using the semiconductor light-emitting device must be controlled precisely in its output wavelength. Accordingly, a conventional optical module has a mechanism for monitoring the output wavelength by receiving light emitted from a rear surface of the light-emitting device. Such optical module is disclosed in a Japanese patent specification laid open 2000-223747.
In recent optical communication system, especially in the WDM system, a transmission speed or a signal frequency increases to some gigabit or more. In order to operate the optical module for such high-speed and high-frequency data, an driver for electrically driving the light-emitting device must be not only enclosed in the package but also arranged side by side configuration with the light-emitting device. However, in the conventional module, since the mechanism for monitoring the output wavelength of the device are disposed between the light-emitting device and the driver, the electrical path between them can not be shortened, thereby suppressing the high frequency performance of the optical module.